On Sun, Dec 31, 2017 at 01:03:25AM +0300, Alexander Tsoy wrote:
Turns out my previous code to print iret frames was a bit ... misguided, to put it nicely. Not sure what I was smoking.
Hopefully the below patch should fix it (in place of the previous patch). Would you mind testing again?
With that patch I get:
[ 2.160017] NMI backtrace for cpu 0 [ 2.160017] CPU: 0 PID: 1 Comm: init Not tainted 4.15.0-rc5 #1 [ 2.160017] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1.fc27 04/01/2014 [ 2.160017] RIP: 0010:double_fault+0x0/0x30 [ 2.160017] RSP: 0000:fffffe8000007fd0 EFLAGS: 00010086 [ 2.160017] RAX: 00000000ffc00000 RBX: 0000000000000001 RCX: 00000000c0000101 [ 2.160017] RDX: 00000000ffff8edc RSI: 0000000000000000 RDI: fffffe8000007f58 [ 2.160017] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 [ 2.160017] R10: 0000000000000000 R11: 0000000000000000 R12: ffffffffa3c01426 [ 2.160017] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 2.160017] FS: 0000000000000000(0000) GS:ffff8edcffc00000(0000) knlGS:0000000000000000 [ 2.160017] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 2.160017] CR2: fffffe8000006f08 CR3: 000000007c153000 CR4: 00000000000006b0 [ 2.160017] Call Trace: [ 2.160017] <#DF> [ 2.160017] RIP: 0010:do_double_fault+0xb/0x140 [ 2.160017] RSP: 0000:fffffe8000006f18 EFLAGS: 00010086 [ 2.160017] </#DF>
Yes, that's more like it. I'll clean up the patches and submit them soon. These nasty bugs are always a good testcase for the stack dump code.
Thanks for testing!